# # 打印 1-10
#
# for i in range(1, 11):
#     print(i)

# 打印从 10 到 1
# num = 10
# while num >= 1:
#     print(num)
#     num -= 1

# for i in range(10, 0, -1):
#     print(i)

# 求 1 + 2 + 3 + ... + 100
sum = 0
for i in range(1, 101, 1):
    sum += i
print(sum)